<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title></title>
		<style>
			* {
				margin: 0px;
			}
			
			.d {}
			
			.w1- {
				background-color: lavenderblush;
				height: 50vh;
				width: 50vw;
			}
			
			.d1 {
				width: 400px;
				height: 200px;
				background-color: lightgray;
				position: relative;
				margin: 50vh 50vw;
				top: -100px;
				left: -200px;
			}
			
			* {
				margin: 0;
				padding: 0;
			}
			
			.div {/*制作扇形*/
				width: 50px;
				height: 50px;
				border-radius: 0 0 50px 0;
				position: absolute;
				background-color: #FC0;
			}
			
			.div- {/*制作扇形*/
				width: 0px;
				height: 0px;
				border-radius: 50px;/*设置表框的圆角,越大越圆*/
				
				border: 50px solid transparent;/*边框的大小和颜色(这里是透明)*/
				
				border-top-color: red;
				border-bottom-color: lavender;
			}
		</style>
	</head>

	<body>
		<div class="d">

			<div class="d1">
				<div class="div">

				</div>

			</div>
		</div>
	</body>

</html>